Multiscale Modeling of Metal-Oxide-Metal Conductive Bridging Random- Access Memory Cells: From Ab Initio to Finite-Element Calculations

J Aeschlimann and F Ducry and C Weilenmann and J Leuthold and A Emboras and M Luisier, PHYSICAL REVIEW APPLIED, 19, 024058 (2023).

DOI: 10.1103/PhysRevApplied.19.024058

We present a multiscale simulation framework to compute the current versus voltage (I-V) character-istics of metal-oxide-metal structures building the core of conductive bridging random-access memory (CBRAM) cells and to shed light on their resistance switching properties. The approach relies on a finite-element model whose input material parameters are extracted either from ab initio or from machine -learned empirical calculations. The applied techniques range from molecular dynamics and nudged elastic band to electronic and thermal quantum transport. Such an approach drastically reduces the number of fitting parameters needed and makes the resulting modeling environment more accurate than traditional ones. The developed computational framework is then applied to the investigation of an Ag/a-SiO2/Pt CBRAM, reproducing experimental data very well. Moreover, the relevance of Joule heating is assessed by considering various cell geometries. It is found that self- heating manifests itself in devices with thin conductive filaments with few-nanometer diameters and at current concentrations in the tens- microampere range. With the proposed methodology it is now possible to explore the potential of not-yet fabricated memory cells and to reliably optimize their design.

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